With the advancement of digital camera manufacturing techniques, electronic devices, which are equipped with a miniaturized and lightweight camera module (e.g., mobile communication terminals), have already been commercialized, and have gradually made inroads into the compact digital camera market. As a mobile communication terminal, which is generally carried by a user, is equipped with a camera module, the user may easily use various functions (e.g., a video call function and an augmented reality function) as well as the function of photographing a still image or a moving image.
As it has become common to mount a camera module to an electronic device, efforts are now being made to improve the performance of the camera module (e.g., image quality) while miniaturizing the camera module. A technique to improve the performance of the camera module includes, for example, an automatic focusing function. The automatic focusing function refers to a function of moving a lens, which is positioned in front of an image sensor, or the image sensor along an optical axis direction depending on a distance to a subject. The automatic focusing function allows a clear image to be obtained on an imaging face of the image sensor. While the automatic focusing function has been equipped in camera modules of high-priced electronic devices, the automatic focusing function has now become an essential function that is mounted to the camera module of inexpensive popular electronic devices.